George Haycock was the Ferdinand James de Rothschild professor of paediatrics at Guy’s, King’s and St Thomas’ Hospitals School of Medicine, King’s College, University of London, from 1990 until his retirement in 2005.

He was born in Buxton, Derbyshire, the son of Charles Burdett Haycock, a headmaster, and was educated at Truro Grammar School, Cornwall, and Gonville and Caius College, Cambridge, where he was an exhibitioner in natural sciences. From Cambridge he went to St Thomas’ Hospital, London, for his clinical studies.

After qualifying and undertaking his first house post at St Thomas’, he was a house physician at Worthing and then a senior house officer in paediatrics in Derby. In 1967 he moved to St Richard’s Hospital, Chichester. In 1969 he became a paediatric registrar at the Royal Hospital for Sick Children in Bristol, followed by four years as a senior registrar there (from 1970 to 1974).

He undertook a training fellowship in paediatric nephrology at the Albert Einstein College of Medicine, New York, between 1974 and 1976. At that time the Einstein was widely regarded as the premier training unit in the USA in the field of the physiology of the developing kidney and the study of renal disease in childhood.

He then returned to Bristol as a consultant paediatrician and paediatric nephrologist. In 1979 he was appointed as a consultant paediatrician and paediatric nephrologist to the Evelina children’s department at Guy’s Hospital, London.

During his two years as a fellow at the Einstein he worked with another fellow, George Schwartz, on a formula to predict the glomerular filtration rate from plasma creatinine in children. As it happened, at that time a similar formula was being devised in London using a completely different method. The two papers were published within a few weeks of each other in different journals, and it was reassuring to find that the parameters were the same. Since then the method has been used for children throughout the world and has now been introduced, with modification, to enable glomerular filtration rate to be calculated from plasma creatinine in adults.

He was active in clinical research throughout his career and published extensively. He had a deep understanding of renal physiology and his papers on sodium wasting by the immature kidney, leading to growth failure in premature infants, were important contributions to improving care. Also important was research showing that volume depletion after surgery leading to hyponatraemia was a dangerous but avoidable complication. A major area of research was concerned with understanding the biochemical consequences of chronic renal failure in childhood, which leads to growth retardation, delayed onset of puberty and serious bone disease from hyperparathyroidism. The satisfying result of this research was the ability to ameliorate the changes by dietary means and by reducing intestinal phosphate absorption. This understanding, along with a major programme of treatment by dialysis and transplantation at Guy’s, transformed the outcomes for children with renal failure. In 1984 the unit at Guy’s carried out 42 renal transplants and was by some way the most active in the UK.

The clinical responsibilities were considerable. As well as undertaking three or four clinics (including one in general paediatrics) each week, each consultant shared the responsibility for the inpatient service, which meant being on call one week in three. During such a week night visits to the hospital were invariable, and more than one visit a day, in addition to regular wards rounds, was routine. His clinical expertise matched his research and teaching proficiency. At all times he was kind and considerate with the children and families.

Haycock used his profound knowledge of his subject to excellent effect as a teacher. He took his responsibilities for undergraduate teaching seriously and was much appreciated by his students. He was also in demand around the world as an invited lecturer. He was an examiner to the Royal College of Physicians and for the Royal College of Paediatrics and Child Health, as well as for qualifying examinations at home and abroad. He was also in demand as an expert witness in cases of suspected child abuse by salt poisoning.

After retiring from his chair he became the scientific adviser to the Foundation for the Study of Infant Deaths, where again his knowledge of the physiology of the infant and child was greatly appreciated.

Outside of work, he was an excellent companion with a wide selection of reminiscences and a wonderful sense of humour. He was interested in everything scientific and widely read outside his field. He was a keen sportsman, especially tennis in his youth, and was a dedicated trumpeter all his life, having played in a band both at Cambridge and at St Thomas’.

In 1968 he married Matilda Webb; the marriage was later dissolved. They had a son, who qualified as a nurse and then entered medical school and was near to qualifying at the time of Haycock’s death. Haycock was also survived by his partner, Dorothy Garvie, who is also a fellow of the Royal College of Physicians.